<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title></title>
		<script type="text/javascript" src="../jquery-1.11.2.js" ></script>
	</head>
	<body>
		<div class="a">
			<div class="b"></div>
		</div>
	</body>
	<script>
		var aa = $('.a').clone(true);
		$('.a').html('')
		console.log($('.b').length)
	</script>
</html>
